Cycle Crashed??

[kcisco71]

We have a 40g breeder tank. It currently has 7 guppies. We have a fluval 207 canister filter and only 3 medium sized java ferns.

A week after tetra safe start plus was added, I finally had 0 ammonia, 0 nitrites, and 5 nitrates. I tested 3 days in a row to be sure it was cycled. The next day after the 3rd day with the same readings, the test shows 0 of everything. The next day, the same thing!

What do I do now?

 

[kcisco71]

Also, forgot to add, I did a 20% water change on the 4th day after stable levels. Used Aqueon Water conditioner.

 

[Aiken Drum]

Just to be clear on what you are saying.

You was getting 0ppm ammonia + nitrite, and had 5ppm nitrate. After a water change, you are now getting 0ppm for ammonia, nitrite and nitrate? And you are worried that the lack of nitrate means the cycle has crashed?

A few points.

- Are you sure you are doing the nitrate test properly? If using API liquid test kit, you really have to shake the heck out of bottle #2 or it results in a false 0ppm reading.
- You are still getting 0ppm ammonia and nitrite so there should be no risk to your fish.
- 7 guppies in a 40 gallon is a very low bioload. It could just be that you are producing such low levels of nitrate that the water change reduced nitrate levels to such that your test kit doesnt read it.

Unless your ammonia and/or nitrite starts going up I wouldnt worry too much. These waste products must be going somewhere or you would be seeing them in the test readings.

 

[kcisco71]

Thank you! Yes, we shake the bejeezus out of bottle 2. I guess I didn't think about that. Thank you again!